tc: bpf: generalize pedit action

existing TC action 'pedit' can munge any bits of the packet.
Generalize it for use in bpf programs attached as cls_bpf and act_bpf via
bpf_skb_store_bytes() helper function.

Signed-off-by: Alexei Starovoitov <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Acked-by: Daniel Borkmann <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 280a315..d5cda06 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -59,6 +59,7 @@
 	ARG_PTR_TO_STACK,	/* any pointer to eBPF program stack */
 	ARG_CONST_STACK_SIZE,	/* number of bytes accessed from stack */
 
+	ARG_PTR_TO_CTX,		/* pointer to context */
 	ARG_ANYTHING,		/* any (initialized) argument is ok */
 };